Compound wire



Patented June 12, 1934 UNITED STATES PATENT OFFICE assignors to The Dentists Supply New York, a corporation of New Company of York i No Drawing. Application pec'mber 21, 1931,

Serial No. 582,510

4 Claims.

Our invention has for an object the making of an improved article of manufacture in the form of gold covered wire, more particularly suitable for anchoring pins for artificial teeth and in which 5 the high fusing temperature of the nickel is utilized by the use of a proper covering thereof in the form of the more precious metals such as'silver and gold, with or without palladium or other metalof the platinum group. These covering metals are especially useful in that they protect the nickel from the solvent action of the saliva or other secretions of the mouth and, in general, from oxidation or other chemical re-action due to atmospheric or other sources of attack.

A further object of our invention is to provide an under-layer of silver or silver alloy of suflicient thickness to insure a heavy shield to the nickel While permitting the use of a gold sheath or outer covering of lesser thickness than would otherwise be required, thereby materially cheapening the cost of the compound wire.

As a still further object, we prefer to form the inner sheath or covering, next to the nickel core, of an alloy composed of silver and palladium or other member of the platinum group, whereby a materially higher melting point is assured than where a silver layer alone is employed, and the use of which palladium provides a more desirable union between the gold and the inner sheath.

As silver has a relatively lower melting point than either gold or nickel, it is desirable to raise the melting point of the silver covering to approximately that of gold, and to do this, we prefer to employ an alloy of silver with a metal having a high melting point, such as palladium or other metal of the platinum group which will raise the melting point of the alloy above the melting point of silver and more nearly approximating that of gold, so that when the wire is employed as pins in artificial teeth, the temperature which is required in the manufacturing operation will have less effect upon the alloy than would be the case with silver alone. Furthermore, as it is desirable to use the smallest amount of gold possible as a protecting covering, because of economy, it is desirable to interpose between the nickel and the gold a covering metal of an alloy of silver with which the gold will weld or be easily soldered to by use of a silver-gold solder.

In carrying out our invention, we first prepare a bar of nickel and turn it down to a predetermined diameter, usually about one and onequarter inches. We then provide a seamless tube of silver or silver-alloy which tightly fits over necessity for so great a thickness of gold covering the bar of nickel. We next assemble upon the outside of the silver tube a seamless gold tube which closely fits to the silver tube, but is of relatively less thickness than that of the silver tube. The whole assembly is then preferably passed through which is called a pinching die to draw the precious metal sheathing portions snugly against the nickel core. The whole compound bar is then heated to a welding temperature and the precious metal sheaths welded to the nickel and to each other. When this is accomplish "l, the compound bar as a whole is reduced to wire in the usual manner, the bar being rolled down and subsequently swaged and drawn through dies of the desired diameter. It is important to properly compute the thickness'of the tubes of silver and gold relatively to the diameter of the nickel core, as these thicknesses determine the ultimate thicknesses of the respective protecting covering layers about the nickel.

As before stated, it is preferable that the silver shall be in the form of an alloy with palladium, and this alloy may be one in which the palladium varies from 10% to 30%, thereby providing silver in the greater quantity, namely, from 90% to We do not restrict ourselves in respect to the amount of palladium employed, but the aim is to employ as little palladium as is possible while securing the desired higher fusing or melting point required.

From the foregoing explanation of our invention, it will be seen that we retain the strong core of nickel or other suitable metal having a sheath or covering of silver or silver alloy which provides a protecting covering of greater thickness than the gold heretofore constituting a layer next to the nickel, the silver or silver alloy providing a resistant to the acids of the mouth and thereby reducing to a material extent the as was heretofore required. The resulting product has, therefore, a heavier protecting covering of gold plus silver (or silver alloy) than has heretofore been provided in a precious metal covering as an acid protection to the wire when utilized for anchoring pins for artificial teeth, and at the same time the cost has been materially reduced. While it is evident from this, that while our improved intermediate layer provides some further acid resistance than has heretofore been secured by a gold covering alone to the nickel, our structure preserves all of the beauty of appearance due to the retained lighter covering of gold.

An optional method is to weld a plate 01' gold to a plate of sliver of preferably greater thickness and this composite plate then drawn into a seamless tube with the gold on the outside.

Into this tube, the nickel core is inserted to the nickel core, may be united by means of hard silver solderwhich serves to unite the nickel core to the precious metal covering.

We have described our improved method and product in that particularity which we deem to be the best exposition of our invention, and that which we prefer in commercial practice, but we do not restrict or confine ourselves to the minor or secondary details, as such are susceptible of modification, which may be resorted to as a matter of mechanical skill and without a departure from the spirit of the invention.

Having thus described our invention, what we claim and desire to secure by Letters Patent, is:

1. As an improved article of manufacture, a composite metal wire having a core of base metal, an immediate protecting covering of silver alloy and an extreme outer covering of gold, said silver alloy containing silver and a metal of the platinum group having a relatively high melting point.

2. As an improved article of manufacture. a composite metal wire having a core of base metal, an immediate protecting covering of silver alloy and an extreme outer covering of gold, said silver alloy containing silver and palladium in different proportions by weight.

3. As an improved article of manufacture, a composite metal wire having a core of base metal, an immediate protecting covering of silver alloy and an extreme outer covering of gold, said silver alloy containing silver and a metal of relatively higher melting point.

4. The improved article of manufacture recited in claim 2, wherein further, the article comprises a wire like pin.

CHARLES DIETZ.

JOSEPH O. WHITELEY. 

